RETS 1.8 update transaction - validate-flag values 0|1|2

User: iCheck
URL: /rets/fnisrets.aspx/RANWMLS/update
Having a problem with UPDATE Transaction when sending Validate=1 the server is validating ALL FIELDS instead the partial record of fields sent in the request. The server is acting as if the validate-flag = 2.

RETS 1.8
10.1.2 Validate
Validate validate-flag
validate-flag ::= 0 | 1 | 2
If this entry is set to 0 and there are no errors in the record, the record in the server database is updated.
If this parameter is set to 1, the server expects that the record is not complete and that it will not be stored on the server as a result of this
UpdateAction. The partial record is validated by the host. Any fields that are not provided are not validated. Any fields with the metadata field
"Attributes" set to "Autopop" in the metadata (see Section 11.3.4 ) will have their field values filled in by the server and returned to the client. The
"Autopop" mode is used to automatically populate the fields of the data record. The record in the server database is not updated.
If this entry is set to 2, the server validates all fields and returns any errors found, but does not store the record. The record in the server database
is not updated.

Here is the request to the server (note validate=1 and only 1 update field in the request):

?Resource=Property&ClassName=RS_1&Validate=1&Action=Change_iCheck&Delimiter=09&Record=L_ListingID=50027302%09L_listing_visibility_type_id=2
The server is responding with the following ErrorBlock